Portable agitator for fluidizing bottom solids in tanks

ABSTRACT

A portable agitator is provided for fluidizing contents of a tank car that has settled during shipment. The agitator includes a column that can extend into a tank car through a manway, a wedging assembly for holding the column in place in the tank between the manway and the bottom wall of the tank, and a pivotable impeller platform appended to a distal end of the column. A pair of impellers are mounted on opposite ends of the impeller platform and are operable to stir and fluidize the contents of the tank car.

This is a division of application Ser. No. 07/921,321 U.S. Pat. No.5,282,681 filed Jul. 29, 1992.

BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates to agitators and resuspension units for stirringsettled solids and liquids contained in tanks to produce a fluid slurrythat can be pumped easily to empty the tank. More particularly, thisinvention relates to a portable agitator that can be lowered into a tankthrough a manway and operated to mix solids accumulating in the bottomof the tank with liquids in the tank to produce a free-flowingcharacteristically uniform fluid slurry.

It is well known that many materials contained in a mobile tank car willsettle to the bottom of the tank during shipment. It can be difficult topump settled solids out of a tank car at the time the tank car is beingemptied of its contents. In practice, a mobile tank car is filled withboth solid and liquid waste products obtained from one or more wastegenerators and transported by highway, rail, or water to a wasteconsumer who will empty the waste products from the tank car and thenburn the waste products as a supplemental fuel. For example, wasteproducts can include paints, solvents, resins, adhesives, inks, organicmaterials, and the like. A cement kiln facility is a typical consumer ofwaste products in that it is economical for a cement kiln operator topurchase waste products from a transporter and burn those waste productsin the kiln as a supplemental fuel.

One problem experienced by transporters of waste products derives fromthe partial solidification, agglomeration, sedimentation, and/orprecipitation of the waste homogenates in the tank cars during shipment.Although the waste product may be a homogenate, i.e., a fluid mixture ofparticles distributed somewhat evenly in a liquid, at the time the wasteproduct is poured into the tank car, in many cases, that waste productwill have separated into various layers or phases of solids, sediments,liquids, semisolids, and agglomerated materials by the time the tank carhas reached its destination. It has been observed that some tank carshave arrived at a cement kiln facility with a significant portion oftheir contents in the form of a non-flowable, non-pumpable gelaccumulated in the bottom of the tank car. This settling probleminterferes with the unloading of the waste products from the tank carand also results in high costs for tank car cleaning services. Further,because there are numerous consumers of waste products at widely diversegeographical locations, construction and use of a single centrallylocated tank-emptying facility, including a provision of a permanenttrackside or dockside tank agitator, is uneconomical and impractical.

An agitator that is portable and sized to be inserted through a tankmanway for fluidizing and resuspending settled solids and liquidscontained in the tank would advantageously enable a waste producttransporter to mix and agitate the entire contents of the tank at thedelivery site prior to and during unloading. A portable agitator thatcan be mounted directly to a mobile tank car would be an improvementover conventional agitators. Moreover, a portable agitator could bemoved easily to each place where tank cars are to be unloaded using onlycommon equipment such as a light truck and a small crane or otherlifting device.

The present invention is an improved portable agitator that is able toagitate and fluidize multi-phase materials in a tank so as to resuspendsediments and break down agglomerates and cause the entire contents ofthe tank to be mixed thoroughly. The improved agitator is sized toextend into an interior region of a tank through a manway tube mountedon the tank. The manway tube includes an axially inner end lyingadjacent to the tank and an axially outer end extending away from thetank.

According to the present invention, the improved portable agitatorincludes a frame, means for mixing solid and liquid material containedin the interior region of the tank to produce a free-flowing slurry, andmeans for selectively wedging against the axially inner end of themanway tube to anchor the frame and position the mixing means in theinterior region of the tank. The mixing means and the wedging means aremounted on the frame. The agitator is operable to facilitate unloadingof multi-phase materials in tanks and is engageable with the manway tubeto stabilize the frame and the mixing means inside the tank.

In preferred embodiments, the portable agitator is configured to belowered through the manway tube into the interior region of the tank sothat the mixing means and the wedging means are positioned wholly insidethe interior region of the tank. The mixing means includes one or morerotating impellers for fluidizing the semisolid and solid materialscontained in liquid stored in the tank. Advantageously, the portableagitator is operable to make it possible to unload tanks at faster ratesand reduce variability of the character or chemistry of the materialcontained in the tank during the period of unloading such material fromthe tank.

Illustratively, the wedging means includes a locking arm and means formoving the locking arm relative to the frame against the axially innerend of the manway tube to press and stabilize the frame against thebottom wall of the tank. The locking arm moving means includes a sleevemounted for vertical sliding movement on the frame. The locking arm ismounted on the sleeve to pivot between a vertical position nearlyparallel to the central axis of the sleeve and a horizontal positionperpendicular to the central axis of the sleeve. The locking armincludes an upper edge that is configured to seat against and mate withthe bottom edge of the axially inner end of the manway tube to helpanchor the frame and position the mixing means inside the tank.

The locking arm moving means also includes an upper hydraulic cylinderassembly or some other extensible member that is operable to raise andlower the sleeve on the frame and pivot the locking arm between itsvertical and horizontal positions. This upper hydraulic cylinderassembly can be actuated by remote control to move the wedging meanseasily along the frame and inside the tank into and out of wedgingengagement with the manway tube.

Also, in preferred embodiments, the mixing means includes two separateplatforms pivotably connected to the frame and means for moving theplatforms between projected positions extending in opposite directionsalong a line perpendicular to the longitudinal axis of the frame andretracted positions aligned in side-by-side spaced-apart parallelrelation along lines parallel to the longitudinal axis of the frame.Illustratively, the platform moving means includes a lower hydrauliccylinder assembly or some other extensible member. This lower hydrauliccylinder assembly is mounted on the frame and attached by means of amechanical linkage to two pivot arms which are pivoted by the lowerhydraulic cylinder assembly to move the two separate platforms relativeto the frame between projected and retracted positions.

An impeller is mounted at the distal end of each platform and operableto agitate material in the tank after the platforms have been moved totheir projected positions and the wedging means has been actuated toretain the agitator in a stable position inside the tank. Further, alocking rod and key system is provided to enable a user to lock the twoseparate platforms mechanically in their projected positions by lockingthe frame to a locking rod connected to the lower hydraulic cylinderassembly so as to add to the stability of the agitator in the tankduring use.

The agitator can be adjusted by remote control to assume a collapsedposition streamlined along the length of the frame to make it easy for auser to lower the agitator into the tank through the narrow manway tube.Initially, the upper hydraulic cylinder assembly is actuated to pivotthe locking arm to its vertical position and move the sleeve toward themixing means to a lowered position so as to facilitate insertion of thelocking arm and an upper portion of the frame into the interior regionof the tank through the manway tube. At about the same time, the twoimpeller-carrying platforms are moved by the pivot arms and the lowerhydraulic cylinder assembly to their retracted positions to facilitateinsertion of the mixing means and a lower portion of the frame into thetank through the manway tube. An external winch and cable can be used tolower the collapsed agitator into the tank through the manway tube.

Once the lower portion of the frame is inserted into the interior regionof the tank, the impeller-carrying platforms can be pivoted by the pivotarms and the lower hydraulic cylinder assembly relative to the frame totheir projected positions so that the impellers face away from oneanother in opposite directions. The upper frame is then lowered furtherinto the tank so that a foot of the frame rests on a bottom wall of thetank.

Next, the wedging means is actuated to help stabilize the agitator inthe tank. The hydraulic cylinder assembly is actuated to pivot thelocking arm to its horizontal position and move the sleeve toward themanway tube to a raised position. In this position, the locking armextends in a direction transverse to the manway tube and is wedgedagainst the annular bottom edge of the axially inner end of the manwaytube to urge the frame downwardly in the tank so that the foot of theframe snugly engages a portion of the bottom wall of the tank centeredunder the manway tube. This wedging action advantageously stabilizes theframe inside the tank to enhance operation of the mixing means.

Finally, a key is used to lock the locking rod to the frame to lock theimpeller-carrying platforms in their projected positions.Illustratively, the locking rod extends inside the frame along a part ofits length and includes an inner end connected to the lower hydrauliccylinder assembly and an upper end projecting out of the manway tube tobe accessible to a user located outside of the tank and holding a key.The key extends through a first slot formed in the frame and a secondslot formed in the locking rod to hold the locking rod and keep theimpeller-carrying platforms in their projected positions.

An impeller drive unit including a drive motor is mounted on eachplatform and configured to rotate the impellers to fluidize semisolidand solid contents of the tank. This fluidizing action reduces themulti-phase materials in the tank to produce a free-flowing fluid slurrythat can be pumped easily through a conventional eductor tube to emptythe tank. Each impeller includes a rotatable hub having a plurality ofhinged collapsible blades. By properly wedging, anchoring, andstabilizing the portable agitator inside the tank, impeller motorshaving enough capacity to rotate the impellers to produce ultra-highmixing thrust can be used on the agitator. This makes it possible tooperate the agitator to produce a free-flowing fluid slurry in the tank.

Additional objects, features, and advantages of the invention willbecome apparent to those skilled in the art upon consideration of thefollowing detailed description of a preferred embodiment exemplifyingthe best mode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figuresin which:

FIG. 1 is a side elevation view of a tank car containing a portableagitator in accordance with the invention with portions broken away toshow the agitator wedged in place between a bottom wall of the tank carand an axially inner end of the manway tube to retain a pair ofimpellers and impeller drive units in a stable position inside the tankcar;

FIG. 2 is an enlarged cross-sectional view of the manway tube takenalong line 2--2 of FIG. 1 showing a pair of pivotable locking armsarranged in spaced-apart parallel relation, attached to a slidingsleeve, and moved to engage the annular bottom edge of the axially innerend of the manway tube;

FIG. 3 is an enlarged side elevation view of the portable agitator ofFIG. 1 showing the axially extended configuration of the agitator as itis being inserted into a tank car through a manway tube wherein thelocking arms are in their vertical position, the sleeve is in itslowered position, and the impeller-carrying platforms are in theirretracted positions;

FIG. 4 is a view similar to FIG. 3 showing the configuration of theagitator during pivoting movement of the impeller-carrying platformstoward their projected positions;

FIG. 5 is an enlarged view taken along line 5--5 of FIG. 4 showingattachment of a pivot locking rod to a movable piston included in thelower hydraulic cylinder assembly and used to control pivoting movementof the impeller-carrying platforms relative to the frame;

FIG. 6 is a view similar to FIGS. 3 and 4 showing the configuration ofthe agitator after the impeller-carrying platforms have been pivoted totheir projected positions, the foot of the frame has been seated on thebottom wall of the tank car, and the upper hydraulic cylinder assemblyhas been actuated to pivot the locking arms to their horizontalpositions without moving the sleeve upwardly on the frame;

FIG. 7 is a view similar to FIGS. 3, 4, and 6 but after upward movementof the sleeve relative to the frame to its raised position to retain thelocking arms in engagement with the bottom edge of the axially inner endof the manway tube and thereby retain the front of the frame in snugengagement with the bottom wall of the tank;

FIG. 8 is an enlarged perspective view of the locking rod and keyassembly shown in FIGS. 1, 3, 4, 6, and 7 prior to insertion of a keyinto a slot formed in the locking rod to retain the impeller-carryingplatforms in their projected positions as shown in FIG. 6;

FIG. 9 is an enlarged side elevation view of a manway tube cover of thetype shown in FIG. 1;

FIG. 10 is an enlarged perspective view of the two-piece manway tubecover shown in FIGS. 1 and 9 prior to installation on the frame;

FIG. 11 is a section taken along line 11--11 of FIG. 7; and

FIG. 12 is a section taken along line 12--12 of FIG. 11.

DETAILED DESCRIPTION OF THE DRAWINGS

The portable agitator 10 is easily lowered into the interior region 12of tank car 14 or other vessel (not shown), locked in place in manway 16of tank car 14, and operated by remote control to fluidize multi-phasematerial contained in the interior region 12 as shown in FIG. 1. Theportable agitator 10 is used to disrupt bottom solids (not shown) thataccumulate on bottom wall 18 inside tank car 14 and blend or mix thesesolids with liquids in the tank car 14 to produce a free-flowing,pumpable, homogenized slurry 20. In effect, agitator 10 fluidizes themulti-phase material in interior region 12 so that it can be pumped outof tank car 14 through the eductor tube 22 and outside hose 24 using aconventional pump (not shown). One advantage of using agitator 10 tofluidize material contained in interior region 12 prior to unloading isthat the tank car 14 can be emptied of its contents more easily andcompletely. In this way, more of the tank car contents are salvaged forlater processing, and subsequent clean-up of each emptied tank car 14 ismore simple and less costly.

Referring to FIG. 1, portable agitator 10 includes a split manway cover26, a vertical frame 28 including an upper column 30 and a lower column32, a wedge assembly 34 mounted for movement on upper column 30, firstand second impeller platforms 36, 38 pivotably connected to the lowercolumn 32, and a pair of rotatable impellers 40, 42 mounted to theplatforms 36, 38 to face in opposite directions. The first impeller 40is mounted at the distal end of the first platform 36 and the secondimpeller 42 is mounted at the distal end of the second platform 38. Thefirst and second platforms 36, 38 are connected to the lower column 32at pivot point 44 for pivotable movement relative to lower column 32 andto one another so that impellers 40, 42 can be aimed at various anglesother than just 180° apart in the manner shown in FIG. 1.

An eyelet bolt 46 or the like is mounted to the top end 48 of uppercolumn 30. Bolt 46 is configured to receive a hook 50 appended to awinch cable 52 to permit a crane or other lifting device (not shown) tomove the portable agitator 10 to the tank car 14 prior to unloading andlowering agitator 10 into the interior region 12 of tank car 14 throughan open manway 16.

Referring to FIGS. 1 and 2, manway 16 is a tube including a cylindricalinner wall 54 defining an access port for receiving agitator 10 duringinsertion of agitator 10 into tank car 14. Manway tube 16 also includesan axially inner end 56 having a circular bottom edge 58 facing towardthe bottom wall 18 of tank car 14. Split manway cover 16 includes asemicircular first cover 60 that mates with a semicircular second cover62 and rests on a circular top edge 64 of an axially outer end 66 ofmanway tube 16 as shown in more detail in FIGS. 9 and 10.

The lower column 32 of frame 28 includes a foot 68 that is configured toseat on a portion of the bottom wall 18 of tank car 14 centered undermanway tube 16. The foot 68 is sized and shaped to help support theweight of the agitator 10 once it is lowered to the working positioninside the interior 12 of tank car 14 shown in FIG. 1.

The wedge assembly 34 includes a sleeve 70 mounted for sliding movementon the upper column 30 of frame 28 and a pair of locking arms 72arranged in spaced-apart parallel relation and mounted to pivot pin 73for pivoting movement on the sleeve 70. An upper hydraulic cylinderassembly 74 is provided for pivoting the locking arms 72 betweenvertical and horizontal positions and moving the sleeve 70 betweenraised and lowered positions. Illustratively, the upper hydrauliccylinder assembly 74 includes an extensible member that is coupled atits base to the lower column 32 and at its tip to a pivot pin 76appended to the locking arms 72. As shown best in FIG. 2, pivot pin 76cooperates with another cross member 80 to hold the pair of locking armsin fixed spaced-apart relation straddling the sleeve 70 and the uppercolumn 30. Stop member 78 is fixed to a side wall 82 of sleeve 70 asshown in FIGS. 1 and 2 to engage the bottom edges 84 of locking arms 72and thereby limit pivoting movement of the locking arms 72 relative tosleeve 70 to define the transverse, horizontal position of the lockingarms 72.

Illustratively, another extensible member is used to control collapsingand unfolding of the pivoting first and second impeller-carryingplatforms 36, 38. A pair of pivot arms 86, 88 and a lower hydrauliccylinder assembly 90 are provided for controlling pivoting movement ofthe first and second impeller platforms 36, 38 relative to the lowercolumn 32 between projected and retracted positions. It will beunderstood that various pneumatic, mechanical, or electrical systems canbe used in lieu of the various hydraulic systems described in thisspecification to move the movable components in portable agitator 10.

First impeller 40 includes a drive shaft 92 mounted for rotation to theleft side of the first impeller platform 36 and a plurality of impellerblades 94 pivotably mounted to the drive shaft 92. Each impeller blade94 is able to pivot toward and away from the longitudinal axis ofrotation of drive shaft 92 so that the impeller blades 94 can moveautomatically under gravity to assume the collapsed position shown inFIG. 3 during insertion of the portable agitator 10 into the tank car14. All of the blades 94 will move to the spread position shown in FIGS.1 and 6 as soon as first impeller 40 begins to rotate.

A drive unit 96 is mounted inside the left end of first impellerplatform 36 and connected to drive shaft 92. Drive unit 96 includes aheavy-duty impeller motor and is operable to rotate drive shaft 92 aboutits longitudinal axis of rotation, thereby causing the impeller blades94 connected to drive shaft 92 to rotate and urge nearby liquids andsolids in an outward direction 98 away from the first impeller platform36 as shown in FIG. 1.

Second impeller 42 is similar in construction to first impeller 40 inthat it includes a drive shaft 110 mounted for rotation to the rightside of the second impeller platform 38 and a plurality of impellerblades 112 pivotably mounted to drive shaft 110. Each impeller blade 112is able to pivot toward and away from the longitudinal axis of rotationof drive shaft 110 during pivoting movement of the second impellerplatform 38 relative to lower column 32.

A drive unit 114 is mounted inside the right end of the second impellerplatform 38 and connected to drive shaft 110. Drive unit 114 alsoincludes a heavy-duty impeller motor and is operable to rotate driveshaft 110 about its longitudinal axis of rotation, thereby causing theimpeller blades 112 connected to drive shaft 110 to rotate and urgenearby liquids and solids in an outward direction 116 away from thesecond impeller platform 38 as shown in FIG. 1. In a preferredembodiment, drive units 96 and 114 are operated so that drive shafts 92and 110 rotate in opposite directions to establish a counter-rotatingrelationship between the left and right impellers 40, 42. Such acounter-rotating relationship helps to stabilize the impeller platforms36, 38 during operation of impellers 40, 42 and permits the impellers40, 42 to be operated to produce ultra-high mixing thrust. It is withinthe scope of this invention to operate drive units 96, 114 at differentrates to cause the impellers 40, 42 to rotate independently and atdifferent speeds. This can vary the mixing in the tank to affect flowdynamics within the tank. Also, if one impeller is hung up orobstructed, the other impeller can still be rotated.

Referring to FIGS. 1 and 2, a power supply 120 and control means 122 areprovided to allow a user to operate the upper and lower hydraulicassemblies 74 and 90 by remote control. A plurality of hydraulic hoselines 124 are arranged to connect control means 122 to each of the upperand lower hydraulic assemblies 74 and 90. Preferably, these hose lines124 are enclosed in a passage 126 that is provided inside frame 28 andsealed to the environment by a silicone and polyurethane combination.Accordingly, the agitator 10 may be operated without problem while theagitator 10 is fully dry, fully submerged in liquid, or partly submergedin liquid. Each hydraulic assembly 74 and 90 includes sealed hydrauliccylinders and motors and is compatible with a wide range of chemicals.In a presently preferred embodiment, the control means 122 includes aplurality of electric solenoid valves (not shown) that are normallypowered by power supply 120 and that can also be switched manually.

In use, a fully collapsed portable agitator 10 can be lowered into theinterior region 12 of tank car 14 through the access port provided inmanway tube 16 as shown in FIG. 3. Once the agitator 10 is lowered toabout the position shown in FIG. 4, the lower hydraulic cylinderassembly 90 can be actuated to pivot the impeller-carrying platforms 36,38 outwardly toward their projected positions.

Illustratively, the lower hydraulic cylinder assembly 90 includes afixed cylinder 128 and a movable piston 130. Piston 130 is mounted forreciprocating movement inside an internal passageway 132 formed in lowercolumn 32. Cylinder 128 has one end fixed to lower column 32 at mount134. Guide pins 136, 138 are coupled to lower hydraulic cylinderassembly 90 as shown in FIG. 5 and arranged to slide in the two axiallyspaced-apart vertical slots 140, 142 formed in lower column 32. Guidepins 136, 138 help to control sliding movement of the piston 130 as itreciprocates in internal passageway 132 along the length of lower column32 during pivoting movement of the impeller-carrying platforms 36, 38about pivot point 44.

The agitator 10 is unfolded further to the position shown in FIG. 6 byusing the lower hydraulic cylinder assembly 90 to pivot theimpeller-carrying platforms 36, 38 to their projected positions.Referring to FIG. 5, a pair of lift arms 143 are provided to swing thepivot arms 86, 88 in and out (as shown in FIG. 4) in response tomovement of the piston 130 up and down in the lower column 32. Each liftarm 143 includes a lower end 145 coupled to one of the guide pins 136and an upper end 147 coupled to one of the other guide pins 138. Theseleft arms 143 serve to connect the distal end of the movable piston 130and the upper guide pins 138 to the pivot arms 86, 88. The agitator 10is unfolded by actuating the lower hydraulic cylinder assembly 90 tomove the piston 130 up with respect to cylinder 128, which causes upperguide pins 138 and the two lift arms 143 attached to guide pins 138 alsoto move up toward manway 16. The lift arms 143 are thus raised to movelower guide pins 136 upwardly in lower slots 140, thereby lifting theupper ends of the pivot arms 86, 88 and causing the pivot arms 86, 88 tolift the impeller-carrying platforms 36, 38 such that those platforms36, 38 pivot about pivot point 44 as shown in FIG. 4. The agitator 10 iscollapsed by reversing of the foregoing steps.

The agitator 10 is then lowered further to cause the foot 68 on thebottom end of lower column 32 to engage the bottom wall 18 of tank 14 asshown in FIGS. 6 and 7. The foot 68 is centered underneath the manwaytube 16 and sized to support the frame 28 as the wedge assembly 34 ismoved by the upper hydraulic cylinder assembly 174 into engagement withthe axially inner end 56 of manway tube 16 as shown in FIGS. 6 and 7.

Illustratively, the upper hydraulic cylinder assembly 74 includes afixed cylinder 144 and a movable piston 148. Cylinder 144 has one endpivotably mounted to a bracket 146 appended to lower column 32 andpiston 148 has a head extending into cylinder 144 and a rod pivotablycoupled to the pivot pin cross member 76 joining the two locking arms 72as shown best in FIGS. 2 and 6.

The wedge assembly 34 is moved from its vertical position shown in FIG.4 to its horizontal position engaging manway 16 as shown in FIG. 7 inthe following manner. First, when the agitator 10 has been lowered tothe position shown in FIG. 6, the upper hydraulic cylinder 74 isactuated to project piston 148 in direction 150 a first distance out offixed cylinder 144 to cause the locking arms 72 to pivot about pivot pin73 from the vertical position shown in FIG. 4 in direction 152 to assumethe horizontal position shown in FIG. 6. During such pivoting, thesleeve 70 remains in its lowered position on upper column 30 as shown inFIGS. 4 and 6. Next, the piston 148 is projected further out of fixedcylinder 144 to cause the locking arms 72 and the sleeve 70 to moveupwardly in direction 154 to the raised position shown in FIG. 7. Inthis raised position, the tapered top edges of the two locking arms 72engage the circular bottom edge 58 of the axially inner end 56 of manwaytube 16 as shown in FIGS. 2 and 7. By using the upper hydraulic cylinderassembly 74 to load the tapered edges of the locking arms 72 againstmanway tube 16, it is possible to center the agitator 10 in manway tube16 and wedge the frame 28 in a snug position between manway tube 16 andtank floor 18 without permanently deforming either the manway tube 16 orthe tank floor 18. This wedging action serves to stabilize the frame 28and the agitator components mounted on the frame 28 in a secure uprightposition to enhance operation of the agitator 10 during use.

Referring back to FIG. 6 and ahead to FIG. 8, it will be seen that alocking key 156 can be used to connect a pivot locking rod 158 to theframe 28 so as to lock the impeller-carrying platforms 36, 38 in theirprojected positions. Pivot locking rod 158 is mounted for reciprocatingmovement in a vertical rod sleeve 160 as shown in FIGS. 8 and 10-12. Therod sleeve 160 is mounted to lie inside internal passageways 126, 132formed in the upper and lower columns. As shown best in FIG. 5, a bottomend 162 of pivot locking rod 158 is coupled to the distal end of pistonrod 130 at upper guide pins 138. As shown best in FIG. 8, a top end 164of pivot locking rod 158 is formed to include a key-receiving slot 166and a lift tab assembly 49, which assembly 49 is coupled to the top endof upper column 30 and is formed to include a pair of key-receivingapertures 168. A chain 170 is provided to tether the key 156 to theframe 28 and a cotter pin 172 is provided to retain the key 156 in itsimpeller platform-locking position passing through slot 166 andapertures 168 as shown in FIGS. 1, 6, and 7.

In effect, the key 156 operates to block movement of pivot locking rod158 and movable cylinder 128 relative to the frame 28. This serves tolock the impeller platforms 36, 38 in their projected position becausethe movable piston 130 is connected to the impeller platforms 36, 38directly by a linkage comprising the first and second pivot arms 86, 88,the lower guide pins 136, the lift arms 143, and the upper guide pins138 which are coupled to movable piston 130.

As shown in FIG. 8, the lift tab assembly 49 includes a central lift tabplate 51 and a pair of spaced-apart parallel lift tab bolt plates 53.Each bolt plate 53 is formed to include a plurality of elongatedbolt-receiving slots 55. Bolts 57 extend through slots 55 and intoapertures 59 formed in top end 48 of upper column 30. These bolts 57 canbe tightened to lock the lift tab assembly 49 in place on the uppercolumn 30. By raising and lowering assembly 49 on column 30, it ispossible to vary the included angle between the impeller-carryingplatforms 36, 38 in their locked positions because of the change inposition of the pivot-locking rod 158. In other words, by adjusting thelift tab assembly 49 up or down on the upper column 30, it is possibleto change the pinning location of pin 156 up or down from the locationshown in FIG. 8 to vary the position of the impellers and platformsbetween angled positions above or below the horizontal position shown inFIG. 6.

The configuration and assembly of the split manway cover 26 isillustrated in FIGS. 9 and 10. As noted previously, cover 26 includes afirst cover 60 and a second cover 62. The first cover 60 includes anotched semicircular plate 174 including an L-shaped flexible sealinggasket 176 attached to the plate 174 to border the notch 178 byhold-down plates 180 and a pair of spaced-apart cover tabs 182. Thesecond cover 62 includes a notched semicircular plate 184 including anL-shaped flexible sealing gasket 186 attached to the plate 174 to borderthe notch 188 by hold-down plates 190. A mounting plate 192 including aspaced-apart pair of upright tabs 194 is mounted along the straight sideof plate 184 on either side of the notch 188 to mate with the cover tabs182 upon movement of the plates 174, 184 to abut one another. A lockingpin 196 can be passed through apertures 198 formed in tabs 182, 194 tohold the covers 60, 62 in abutting sealing relation on the top of themanway tube 16.

A vapor discharge outlet 210 is mounted on the second cover 62 toconduct various vapors extant in the interior region 12 of tank 14 to avapor handling means 212 (FIG. 1) through a conduit 213 during operationof the agitator 10 in tank 14. A threaded cap 214 is provided to closevapor discharge outlet 210 until it becomes necessary to vent the tank14 to the vapor handling means 212.

The connection of the upper column 30 to the lower column 32 to providethe upright frame or mast 28 is illustrated in FIGS. 11 and 12. A cap216 is provided inside lower column 32 to organize and arrange thehydraulic hose lines 124 and the pivot locking rod 158 and rod sleeve160 passing between the two columns 30, 32. The lower end of rod sleeve160 terminates in a central slot 218 formed in cap 216 as shown in FIG.12.

In practice, to use the portable agitator 10 it is necessary to spot andblock the tank car 14, hook grounding to the tank car 14, and vent andopen the tank car manway 16. The agitator 10 is swung on a crane or thelike to lie over the access port in manway tube 16. Preferably, theagitator 10 is oriented diagonally to place the impellers 40, 42 at 5o'clock and 11 o'clock if, when looking down on the access port opening,the 12 o'clock position is toward a long end of the tank car 14. Theagitator 10 is then lowered (about eight feet) into the tank car 14until the locking arms 72 line up with the top edge of the manway 16.

The impeller-carrying platforms 36, 38 are then pivoted upwardly toassume their projected positions as shown in FIGS. 6 and 7. The agitator10 is then rotated about the longitudinal axis of the vertical frame 28to contact any vertical obstructions (e.g., valve stems and siphonpipes) present in the interior region 12 of tank car 14. If noobstructions are detected, the agitator 10 is rotated to line up theimpeller platforms 36, 38 along the long center line of tank car 14. Thewedge assembly 34 is then used to wedge frame 28 securely in placebetween the manway tube 16 and the tank floor 18.

The two-piece split closure plate 26 is then installed around the uppercolumn 32 to close and seal the opening in manway tube 16. Now the vaporlines are connected and the impellers 40, 42 are then turned on to mixthe contents of the tank car 14 thoroughly.

Although the invention has been described in detail with reference tocertain preferred embodiments, variations, and modifications existwithin the scope and spirit of the invention as described and defined inthe following claims.

I claim:
 1. A portable agitator for extending into an interior region ofa tank through a manway tube mounted on the tank to fluidize materialcontained in the tank, the manway tube including an axially inner endlying adjacent to the tank and an axially outer end extending away fromthe tank, the agitator comprisinga frame including an upright column andfoot means for engaging a bottom wall in the tank to stabilize theupright column in the interior region of the tank, means for mixingsolid and liquid material contained in the interior region of the tankto produce a pumpable slurry, the mixing means being mounted on theframe and including first and second platforms, each platform beingpivotably connected to the upright column to move between a retractedposition situated to lie alongside the upright column to facilitateinsertion of the platform into the interior region of the tank throughthe manway tube and a pivoted position oriented to lie at an angle tothe longitudinal axis of the upright column, a first impeller rotatablymounted on a distal end of the first platform and arranged to face in afirst direction, a second impeller rotatably mounted on a distal end ofthe second platform and arranged to face in a second direction oppositeto the first direction, a drive member, means for slidably mounting thedrive member to the upright column for reciprocating movement relativeto the upright column, a first pivot arm having a first end pivotablycoupled to the first platform and a second end pivotably coupled to thedrive member, a second pivot arm having a first end pivotably coupled tothe second platform and a second end pivotably coupled to the drivemember, and means for reciprocating the drive member between aplatform-projecting position to move the first and second platforms totheir pivoted positions by pivoting the first ends of the first andsecond pivot arms away from the upright column and a platform-retractingposition to move the first and second platforms to their retractedpositions by pivoting the first ends of the first and second pivot armstoward the upright column, and means for selectively wedging against theaxially inner end of the manway tube to anchor the frame and positionthe mixing means in the interior region of the tank, the wedging meansbeing mounted on the frame.
 2. The agitator of claim 1, wherein themixing means is mounted on the frame to lie between the foot means andthe wedging means.
 3. The agitator of claim 1, wherein the reciprocatingmeans includes a cylinder fixed to the upright column and a movablepiston assembly coupled to the cylinder and to the drive member.
 4. Theagitator of claim 3, wherein the reciprocating means further includesmeans for moving the piston assembly relative to the cylinder to movethe drive member between its platform-projecting and platform-retractingpositions.
 5. The agitator of claim 4, wherein the upright column isformed to include a key-receiving aperture, and further comprising apivot locking rod coupled to the piston assembly to move therewith andformed to include a key-receiving slot and key means for passing throughthe key-receiving aperture and slot simultaneously to lock the pivotlocking rod to the upright column so that the first and second platformsare retained by the pivot locking rod, piston assembly, and drive memberin their pivoted positions.
 6. The agitator of claim 1, wherein thedrive member includes a pin and the mounting means includes apin-receiving slot formed in the upright column and configured to guidethe pin along a straight path during reciprocation of the drive member.7. The agitator of claim 1, wherein the upright column is formed toinclude a key-receiving aperture, and further comprising a pivot lockingrod formed to include a key-receiving slot, means for connecting thepivot locking rod to the drive member for movement therewith, and keymeans for passing through the key-receiving aperture and slotsimultaneously to lock the pivot locking rod to the upright column sothat the first and second platforms are retained by the pivot lockingrod, connecting means, and drive member in their pivoted positions.
 8. Aportable agitator for extending into an interior region of a tankthrough a manway tube mounted on the tank to fluidize material containedin the tank, the agitator comprisinga frame including an upright columnand foot means for engaging a bottom wall in the tank to stabilize theupright column in the interior region of the tank, first and secondplatforms, each platform being pivotably connected to the upright columnto move between a retracted position situated to lie alongside theupright column to facilitate insertion of the platform into the interiorregion of the tank through the manway tube and a pivoted positionoriented to lie at an angle to the longitudinal axis of the uprightcolumn, a first impeller rotatably mounted on a distal end of the firstplatform and arranged to face in a first direction, a second impellerrotatably mounted on a distal end of the second platform and arranged toface in a second direction opposite to the first direction, a drivemember, means for slidably mounting the drive member to the uprightcolumn for reciprocating movement relative to the upright column, afirst pivot arm having a first end pivotably coupled to the firstplatform and a second end pivotably coupled to the drive member, asecond pivot arm having a first end pivotably coupled to the secondplatform and a second end pivotably coupled to the drive member, andmeans for reciprocating the drive member between a platform-projectingposition to move the first and second platforms to their pivotedpositions by pivoting the first ends of the first and second pivot armsaway from the upright column and a platform-retracting position to movethe first and second platforms to their retracted positions by pivotingthe first ends of the first and second pivot arms toward the uprightcolumn.
 9. The agitator of claim 8, wherein the reciprocating meansincludes a cylinder fixed to the upright column and a movable pistonassembly coupled to the cylinder and to the drive member.
 10. Theagitator of claim 9, wherein the reciprocating means further includesmeans for moving the piston assembly relative to the cylinder to movethe drive member between its platform-projecting and platform-retractingpositions.
 11. The agitator of claim 10, wherein the upright column isformed to include a key-receiving aperture, and further comprising apivot locking rod coupled to the piston assembly to move therewith andformed to include a key-receiving slot and key means for passing throughthe key-receiving aperture and slot simultaneously to lock the pivotlocking rod to the upright column so that the first and second platformsare retained by the pivot rod, piston assembly, and drive member intheir pivoted positions.
 12. The agitator of claim 8, wherein the drivemember includes a pin and the mounting means includes a pin-receivingslot formed in the upright column and configured to guide the pin alonga straight path during reciprocation of the drive member.
 13. Theagitator of claims 8, wherein the upright column is formed to include akey-receiving aperture, and further comprising a pivot locking rodformed to include a key-receiving slot, means for connecting the pivotlocking rod to the drive member for movement therewith, and key meansfor passing through the key-receiving aperture and slot simultaneouslyto lock the pivot locking rod to the upright column so that the firstand second platforms are retained by the pivot locking rod, connectingmeans, and drive member in their pivoted positions.
 14. The agitator ofclaims 8, further comprising means for engaging the manway tube to holdthe foot means against the bottom wall of the tank, the engaging meansbeing mounted to the upright column and arranged to position the drivemember between the engaging means and the foot means.
 15. The agitatorof claim 14, wherein the engaging means includes a locking arm, meansfor supporting the locking arm for movement relative to the framebetween manway tube-engaging and manway tube-disengaging positions, andmeans for moving the locking arm between its manway tube-engaging anddisengaging positions.
 16. The agitator of claim 15, wherein thereciprocating means includes a first piston and cylinder assemblymounted on the upright column and the moving means includes a secondpiston and cylinder assembly mounted on the upright column.